Method and apparatus for development of film



June 6, 1967 c. H. HAF'ER ETAL. 3,323,436

METHOD AND APPARATUS FOR DEVELOPMENT OF FILM Filed March 17, 1965 CITRICACID MG 1% i CAMERON H. HAFER HQ. 2 CAMILLE A. PLANTE BY M @W AGE/VTUnited States Patent 3,323,436 METHGD AND APPARATUS 'FGR DEVELQPMENT 0FFILM Cameron H. Hafer, Apalachin, and Camille A. Plante,

Johnson City, N.Y., assignors to International Business MachinesCorporation, Armonk, N.Y., a corporation of New York Filed Mar. 17,1965, Ser. No. 440,485 9 Claims. (Cl. 95-89) This invention relates todeveloping apparatus for sensitized materials and more particularly toan improved gaseous developing chamber used in connection with thedevelopment of ammonia process diazotype films and papers.

The present invention is especially significant in the mechanizedproduction of diazo film duplicates of either silver or diazo filmoriginals. Such film duplicates commonly occur as the analogue storagesection of a socalled aperture card, that is to say, a punchedtabulating card in which a section of the card has been removed andreplaced with a piece of light-sensitive film. With documentminiaturization technology approaching the point where the ability toresolve 1000 lines/mm. is becoming essential, diazo films are a firstchoice in such applications. Heretofore, however, the use of such diazofilm aperture cards has been limited to so-called off-line applicationssince the ammonia developing process as heretofore practiced has beentoo slow and problem-ridden to make practical its use in an on-lineinformation storing and disseminating system.

Until recently, the ammonia developing process was largely adaptedto theneeds of diazo papers and, as is well known, the common practice is touse aqua ammonia as a source of ammonia along with the presence of heat.Aqua ammonia is dripped into a heated container Where substantially allof the ammonia together with a considerable proportion of thewater-solvent is vaporized. Diazo paper or film is brought into contactwith the hot, moist ammonia fumes by sliding the paper acrossperforations in a chamber or in some cases, by direct introduction ofthe film or paper into the chamber itself through sealing rolls. Withthis type of process, experience indicates that heat and a certaindegree of moisture are quite essential in suitably developing diazopapers.

The employment of hot vapors of aqua ammonia for development hasproduced a number of difficulties. If an attempt is made to developfilms and papers at ambient temperatures, the development is extremelyslow with more than one pass through the development chamber oftentimesbeing required, the shades obtained are nontypical, and thus the processis quite unsatisfactory. In diazo products which contain severalcouplers and/or several diazos in order to secure a desired color, theactual shades obtained are found to depend to a great degree on theactual conditions of development. Thus, a hot, dry developingenvironment is prone to produce blue prints, while a cool, moistenvironment tends to yield yellow-brown hues. This is due to avariability in relative coupling rates with temperature. The amount ofwater present also creates problems in that too low a proportion ofwater leads to poor development and off-color shades, while too high aproportion of water leads to sodden prints, dye bleed, streaking, papercockling and false colors. And of course in view of the high resolutionrequirements of the aperture card film pieces, no degree of dye bleedcan be tolerated during development.

The above outlined difficulties associated with paper products becomeeven more predominate in connection with developing diazo film products.Diazo films generally comprise a suitable transparent base, frequently atough, dimensionally stable, polyester film to which has been bonded aresin matrix suitable for diazo sensitization. Sensitization is normallydone by the use of a solventsensitizing component containing mixture.Cellulose acetate is typical of a suitable sensitizing layer. In view ofthe water-resistant characteristics of typical diazo film matrices, itcan be understood that difiiculty ensues when aqua ammonia is employed.In addition to certain of the developing difiiculties mentioned forpaper, new difiiculties arise, such as a tendency for the film to blushand haze under certain conditions of moisture and heat and a markedslowing down of the development rate owing to the difiiculty in securinga rapid penetration of the layer by the ammonia-water mixture.Furthermore, water-induced curl, always a major difiiculty with paper,can become uncontrollable with certain types of films.

Finally, a major source of difficulty with the development procedurescurrently employed, is a loss of resolution owing to diazo diffusionduring the relatively slow development process. As noted earlier,photomaterial technology is approaching the point where the ability toresolve 1000 lines/ mm. is becoming essential. In order to accomplishthis high resolution, it is fundamental that the image pattern laid downby light be preserved during subsequent processing steps. This impliesthat the motion of the imaging species during development can be only afew hundred molecular diameters. Clearly, in the case of the diazo filmprocess, it is essential that the developing process be aimed atminimizing diazo diffusion; that is, that the diazo must be immobilizedby dye formation as rapidly as possible. It is well known that diffusionrates are increased by an increase in temperature so that lowtemperature development is desirable. Further, it is necessary that aneffective quantity of the developer composition he infused as rapidly aspossible to the full depth of the resin matrix bearing the diazo image.The ammoniawater developer system is clearly not adapted to theattainment of these objectives, and, in fact, severe degradation ofimage resolution owing to diazo diffusion can be demonstrated in diazosystems in which heat during development is the prime factor in securingsatisfactory image development.

In overcoming the above shortcomings of the ammonia-water developersystem, there has been recently brought to light an improved system bywhich the development of both diazo films and papers may be carried outat ambient temperatures instead of the elevated temperatures hithertoused. This system is fully set forth in United States patent applicationSer. No. 369,861, entitled, Diazo Development Process, assigned to theassignee of the present application. The improved process utilizes aliquid ammonia environment as a reaction solvent which results from theuse of essentially pure ammonia gas or. anhydrous ammonia at a pressuresufficiently high that condensation of the gas can be expected to occurthroughout the molecular pores of the matrix, be it film or paper. Thecoupling reaction is thus deemed to occur in a surround of liquidammonia solvent .instead of an aqua ammonia surround. In spite of thefact that low temperature conditions are employed at which a lowering ofdevelopment rate would be expected, there is actually achieved anincrease in development rate of the order of hundreds of. times thatpossible with aqua ainmonia under the same conditions. Development is sonearly instantaneous that in combination with the relatively lowtemperatures employed, substantially no diazo diffusion occurs beforethe diazo is immobilized by dye formation. Also, an essentially constanttemperature is possible so that relative coupling rates remain constant.The speed of the process results in a constant development time andblotch, haze and curl in forms are substantially reduced or eliminated.The sensitometric and color fidelity, the extreme rapidity ofdevelopment and the very high efiiciency with which ammonia is usedmakes the process especially compatible with existing accountingmachines so that online processing of aperture cards and aperture cardduplicates becomes practical for the first time with ammonia developingsystems.

One of the proposed methods for carrying out development by the improvedhigh pressure process involves sandwiching a piece of film or paperbetween two closely fitting surfaces so that very little dead space orvolume remains, Suitable gasketing means is provided to contain thematerial to be developed and, of course, a tight seal between the filmand the developer platen is required. Then means are provided forintroducing ammonia at slightly above ambient saturation pressure(usually from about 90 to 120 p.s.i. absolute) for a dwell time measuredin fractions of a second (usually about 0.8 second suffices), followedby essentially instantaneous reduction in ammonia fumes allowed toescape to the atmosphere, either by pumping or by flushing the chamberinto a vessel containing an ammonia absorbent.

Several types of apparatus are being proposed for carrying out the abovedescribed high pressure ammonia system' with particular emphasis beingplaced on a good tight film to developer platen seal, good control ofthe high pressure ammonia, and complete uniformity of development.Typical apparatus proposed are shown in United States patent applicationSer. No. 430,094, entitled, Wash Ammonia Development Device, assigned tothe assignee of the present application.

It is recognized that a problem exists with regard to obtaininguniformity of development due to the fact that before the high pressureammonia is actually applied and at the time that the film and developerplaten are brought together to effect a tight seal, air becomesentrapped between the film and platen developer cavity. If not removed,this entrapment of air impedes the action of the ammonia on the emulsionsurface of the film and causes underdevelopment of the film in certainareas. In working on several solutions of this problem, it was foundthat the entrapped air can be completely removed and excellent resultsobtained with regard to uniform development of the film by utilizing theincoming high pressure ammonia to positively drive or wash the entrapped.air out of the developer cavity and remove it away from the surface ofthe image area of the film as that area is about to be developed.

To effectively carry out this wash approach it is necessary to providesomeplace for the entrapped air to go Where it can be contained awayfrom the surface of the film without breaking the tight film todeveloper platen seal and without incurring. any ammonia leakage whichwould reduce the effectiveness of development and which would alsorelease undesirable fumes to the atmosphere. To accomplish this, asecond cavity is provided into which the entrapped air is driven andthis cavity is preferably located on the opposite or back side of thedeveloper platen so that the air will be contained away from the surfaceof the film. Suitable ports for the flow of ammonia into the developmentcavity and for the flow of entrapped air from the development cavityinto the air cavity are provided, which ports and cavities lie entirelywithin the sealed area of the platen so that there is no leakage ofammonia. Also, suitable valve means are provided for exhausting theammonia into an ammonia absorbent device at the end of each developmentcycle prior to removing the film and breaking the film to platen seal tofurther prevent any ammonia leakage to the atmosphere.

Accordingly, a principal object of the present invention is to provide anovel method of utilizing the high pressure ammonia development processto accomplish high speed, uniform development of sensitized films andpapers with no ammonia leakage.

A further object of the present invention is to provide a novel methodof utilizing the high pressure ammonia development process to accomplishhigh speed, uniform development of a film area and wherein air entrappedbetween the film and development platen is washed away from the filmarea by the incoming ammonia.

Another object of the present invention is to provide a noveldevelopment device for effectively carrying out the Wash developmentmethod of the preceding object.

A still further object of the present invention is to provide a novelhigh pressure ammonia development device having a development platenprovided with a development cavity on one side and an air reservoircavity on the opposite side which is adapted to receive and containentrapped air driven out of the development cavity by incoming ammonia.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of a preferred embodiment of the invention, as illustratedin the accompanying drawings.

In the drawings:

FIG. 1 is a partial sectional view of a preferred em bodiment of a highpressure ammonia development de vice constructed in accordance with theprinciples of the present invention.

FIG. 2 is an enlarged front plan view of the development platen showingthe ammonia development cavity.

FIG. 3 is a vertical sectional view taken on line 3-3 of FIG. 2 showingboth the ammonia development cavity and the air reservoir cavity.

Referring to the drawings and particularly to FIG. 1, the developmentmechanism comprises a 3-way solenoid valve 10, a housing 11, adevelopment platen 12 and a back-up platen 13-. The valve 10 serves tocontrol the introduction of high pressure ammonia into a develop mentcavity 14 recessed in the film side of the development platen and thevalve also serves to exhaust the ammonia out of the development platenand into an absorber device 15 at the end of each development Cycle.

The high pressure ammonia employed may be anywhere in the range of 50 to120 p.s.i.g., however, in actual practice, it is preferable to userefrigeration grade ar1- hydrous ammonia at a pressure of :5 p.s.i.g. Inthe present embodiment, the supply is 2 pound ammonia in a number 4bottle, as indicated at 16'. It will be understood that other sizes ofsupply may be used. The 3 way valve 10 is attached to the housing 11 andthe ammonia supply 16 is connected to a passageway 17 in the valve byway of a turn on-turn off valve 18 and a pressure regulator 18a. Asindicated in FIG. 1, at sub stantially room temperature of 70 F., forexample, the pressure of the ammonia in the bottle 16 would be in theorder of 128 p.s.i.g. The pressure would decrease under decreasedtemperature conditions and increase under increased temperatureconditions. Therefore, the pressure regulator 18a is provided toregulate the ammonia pressure so that it will be preferably at 80p.s.i.g. when it enters the valve 10. When development of film is not totake place, a solenoid member 19 in the 3-way valve Will be in its downposition, as shown in FIG. 1, to seal off passageway 17 and prevent theammonia from reaching the development cavity 14.

Referring particularly to FIGS. 2 and 3, in the present embodiment, thedevelopment platen 12 comprises a circular metallic member having asubstantially rectangular recessed area in one side which defines therelatively thin development cavity 14. The configuration of the cavityis shown as being substantially rectangular to correspond to theconfiguration of the image area of the film pieces generally mounted inaperture cards but, of course, it will be understood that anyconfiguration could be used. The development cavity 14 is on the filmside of the platen and is necessarily thin, having a preferred depth inactual construction of .010 inch. A thin develop ment cavity is deemedimportant since it will minimize the amount of air that becomesentrapped between the film piece and the cavity and at the same time itwill enable the inrushing ammonia to wash or drive out of the cavitywhat air is entrapped and to uniformly develop the film image area moreeffectively and with greater speed and also to reduce the amount ofammonia used.

Bordering around the outside of the development cavity is a rubbersealing ring which protrudes from the surface of the platen 12 byapproximately .020 inch. When the back-up platen 13 positions the filmpiece against the sealing ring 20 and the high pressure ammonia isadmitted to the development cavity, an absolutely leak proof chamber isformed about the emulsion side of the film and the escape of ammonia gasis eliminated thus eliminating odors and allowing the high concentrationof ammonia in the cavity to effect uniform development of the film.

On the reverse or back side of the development platen there is formedanother recessed area which defines an air entrapment cavity orreservoir 21 into which the entrapped air in the development cavity 14is driven and contained. Although not necessary, excellent results havebeen obtained with the entrapment cavity 21 provided with the sameconfiguration as the development cavity and located in alignmenttherewith. Also, in actual construction, the air cavity 21 is given adepth of approximately .015 inch. The resulting 2:3 ratio in volumebetween the development cavity and the air reservoir cavity has provento be ideal in actual operation of the development mechanism.

As shown in FIG. 2, a central entrance port 22 is provided in the platenfor admitting the high pressure ammonia'into the development cavity 14substantially at the center thereof and ten ports 23 are provided whichare equally spaced around the edges of the cavities to communicate thetrapped air in the development cavity back to the reservoir orentrapment cavity 21. In actual construction, the ports 22 and 23 aregiven a diameter of approximately .031 inch. With this preferredarrangement of ports, the incoming ammonia from the central port 22 isable to diffuse effectively and instantly spread in all directions tofill the development cavity and contact all portions of the film imagearea at substantially the same time to carry out uniform development.Also, the arrangement of the ring of ports 23 around all extremities ofthe cavities allows all of the entrapped. air in the development cavityto be instantly and simultaneously removed from all portions of thedevelopment cavity to further enhance uniform development of the film.It can be seen that with the present arrangement of ports, the entireimage area of the film will be quickly and effectively washed. This isan important and desirable feature.

Provided around the outside of the air cavity 21 is a rubber sealingring 24 which is identical to the sealing ring 20 and screw holes 25 areprovided for screwing the development platen 12 tight against thehousing 11, as shown in FIG. 1, so that the air cavity is leak proof.The platen is mounted so that the central port 22 is in alignment withpassageway 26 in the 3-way valve 10. Passageway 26 is normally blockedfrom the ammonia supply when the solenoid member 19 is in its downposition, as shown. A rubber O-ring seal 27 is provided to seal theconnection between the valve and the central port 22 to prevent theincoming ammonia from leaking into the air cavity 21.

In the operation of the mechanism, a film record card 28 would besuitably transported from an exposure station, for example, to, aposition between the back-up platen 13 and the development cavity 14. Asshown in FIG. 1, the film card 28 may be of the well-known type whichusually comprises cardstock of approximately .007 inch thickness, anapertured area 29-having a recessed shoulder around its perimeter, and afilm piece 30 secured over the aperture and to the recessed shoulder.The film piece may have a thickness which varies, for example, from .003to .005 inch. A suitable movable card stop (not shown) is employed tolocate the card and, of course, the emulsion side of the film piecewould be toward the development cavity. The card is located so that theimage area on the film piece will be confined within the sealing ring 20when the card is pushed against the development platen.

After the card has been properly located, a suitabie toggle mechanism(not shown) operates to push the backup platen and card against thedevelopment platen. The image area of the film is positively heldadjacent to the development cavity 14 during the development cycle withthe ring seal 20 effectively sealing the resulting development chamberformed by the cavity and film.

Next, the solenoid member 19 is operated upwardly, from the positionshown in FIG. 1, to effectively seal oif an exhaust passageway 31 whichis connected to the absorbent device 15 and also to open up thepassageways 17 and 26. The high pressure ammonia from source 16 is nowfree to flow through the passageways 17 and 26 and the central port 22to fill the development cavity 14. Air is entrapped in the developmentcavity during the platen sealing operation and the inrushing ammoniagas, spreading out in all directions from the center port 22, instantlyforces or washes the entrapped air to the outside of the chamber andthrough the ten port holes 23 and into the reservoir or air entrapmentcavity 21. Thus, high concentrations of entrapped air, detrimental todevelopment, are instantly displaced or removed from the emulsionsurface of the film and uniform development of the image area quicklytakes place.

The length of development cycle required depends upon the type of diazofilm being developed. In tests made with the present device on two typesof commercially available diazo film identified as Unit Gamma,manufactured by General Aniline and Film Company, and K Tone,manufactured by the Technifax Corporation, it was found that ammonia atp.s.i.g. and at ambient or room temperature fully developed the UnitGamma film in 0.8 second and the K Tone film in 0.25 second.

At the end of the required development cycle the 3- way valve is de-energized to return the solenoid member 19 back down to the positionshown in FIG. 1. As a result, the entrance passageway 17 is closed andthe exhaust passageway 31 is opened to connect the development chamber14 to atmospheric pressure. The spent anhydrous ammonia gas now flowsout of the cavities, back through the center port 22, the passageways 26and 31 and into the absorbent device 15 which contains a suitableabsorbent 32, such as citric acid, or the like.

After the development chamber pressure drops to atmospheric and theammonia gas is exhausted, the backup platen 13 is pulled away from thecard 28 andthe card stop is removed allowing the card to be expelledfrom the device. It is desirable to exhaust the gas and reduce thecavities to atmospheric pressure before the platen seal is broken.

It is important to note that the arrangement of the entry port 22 andthe exit ports 23 is such that the sweeping out of the air by theammonia occurs across the full image area of the film. Also, theplacement of the air entrapment cavity 21 on the reverse or back side ofthe development platen and substantially in the central portion thereofinsures that the entrapped air will be contained during developmentcompletely away from the emulsion surface of the film. Of course, otherarrangements of cavities and ports could be used to carry out theprinciples of the present invention, however, our preferred embodimentdescribedabove provides excellent results.

A distinct advantage of using the present high pressure ammoniadevelopment device in connection with film record cards is that the cardsurrounding the film area does not have to be subjected to an ammoniachamber. This eliminates any wetting or change in color of the carditself. In the preferred embodiment shown, the configuration and area ofthe chambers 14 and 21 are substantially identical to each other andcorrespond to the configuration and area of the film piece to bedeveloped. As such, the material area outside of the sensitized portionto be developed is not affected. Of course, it will be understood thatuse of the present device is not limited to the development of filmrecord cards alone. Any form of photosensitive material may be developedwith equal results such as, for example, unmounted film pieces andemulsion coated papers, which material need not necessarily be of thediazo type. Also, gasses or fluids other than ammonia may be employed.

While the invention has been particularly shown and described withreference to a preferred embodiment thereof it will be understood bythose skilled in the art that the foregoing and other changes in formand details may be made therein without departing from the spirit andscope of the invention.

What is claimed is:

1. A device for developing material by applying a fluid substance underpressure to a sensitized area of said material comprising:

a development platen having a first cavity in one side thereof,

a seal member surrounding said first cavity and shaped to enclose saidsensitized area,

a back-up platen operative to hold said sensitized area against saidseal whereby a development chamber is formed with said first cavity,

a second cavity on the opposite side of said development platen,

sealing means for said second cavity whereby an air entrapment chamberis formed,

a port for conducting said pressurized substance into said first cavitysubstantially at the center thereof whereby said substance will spreadout in all directions throughout said development chamber, and

a plurality of individual ports arranged around the periphery of saidfirst cavity which communicate with said air entrapment chamber wherebyentrapped air in said development chamber is forced by said substance toflow into said air entrapment chamber thus enabling said sensitized areato be contacted by said fluid substance in the absence of air. 2. Adevice for developing material as defined in claim 1 wherein said fluidsubstance comprises anhydrous ammonia at a pressure anywhere in therange of 50 to 120 psi.

3. A device for developing material as defined in claim 1 wherein theconfiguration and area of said development and, air entrapment chambersare substantially identical and correspond to the configuration and areaof the sensitized material to be developed.

4. A device for developing material as defined in claim 1 wherein thevolumes of said development and air entrapment chambers have anapproximate ratio of 2:3, respectively.

5. A device for developing material as defined in claim 1 wherein all ofsaid ports are circular and of the same area, the area of each portbeing quite small'in comparison to the area of said chambers.

6. A device for developing material as defined in claim 1 wherein saiddevelopment and air entrapment cham bers are in alignment with eachother and are located substantially in the central portion of saiddevelopment platen.

7. A device for developing material having a sensitized area comprising:

a development platen having a first cavity in one side thereof,

a seal member surrounding said first cavity and shaped to enclose saidsensitized area,

a back-up platen operative to hold said sensitized area against saidseal whereby a development chamber is formed with said first cavity,

a second cavity on the opposite side of said development platen,

sealing means for said second cavity whereby an air entrapment chamberis formed,

an entrance port opening into said first cavity at substantially thecenter thereof,

a source of pressurized gas adapted to develop said sensitized material,

an absorbent device for said gas,

valve means connected between said source of gas, ab-

sorbent device and said entrance port,

an operating member in said valve means operable to seal ofi saidabsorbent device and admit said gas to said entrance port whereby saidgas will spread out in all directions throughout said developmentchamber, and

a plurality of individual ports arranged around the periphery of saidfirst cavity which communicate with said second cavity whereby entrappedair in said development chamber is forced by said gas to flow into saidair entrapment chamber thus enabling said sensitized area to bedeveloped in the absence of air,

said operating member being operable after development to seal off saidsource of gas and open said absorbent device whereby the gas in saidchambers will flow out of said development platen through said entranceport and into said absorbent device.

8. A device for developing material as defined in claim 7 wherein saidvalve means and operating member effectively reduces said chambers toatmospheric pressure after development and prior to the release of saidbackup platen.

9. A device for developing a sensitized surface on a material byapplying a high pressure developer fluid thereto comprising:

a development platen including a wall with a recessed portion whoseopposite pairs of sides define an outwardly facing rectangular cavityadapted to face the sensitized surface;

a seal member surrounding said rectangular cavity and shaped toencompass the sensitized surface to be developed; 1

a back-up platen operative to hold the material against said seal memberand defining with said cavity a rectangular development chamber for thesensitized surface and wherein air is trapped;

an inner air entrapment chamber disposed in back of said cavity in saidwall;

a plurality of circular ports in said wall and spaced along at least onepair of the opposite sides of said rectangular cavity to directlyconnect said development'chamber with said air entrapment chamber;

a circular entrance port extending through said wall and substantiallycentrally located in said cavity for admitting the high pressuredeveloper fluid into said rectangular development chamber fordistribution throughout; and

said entering developer fiuid simultaneously displacing the trapped airthrough said outlet ports into said air entrapment chamberand spreadingthroughout said rectangular development chamber to contact and developthe entire exposed sensitized surface on the material.

No references cited.

NORTON ANSHER, Primary Examiner.

F. L. BRAUN, Assistant Examiner.

1. A DEVICE FOR DEVELOPING MATERIAL BY APPLYING A FLUID SUBSTANCE UNDERPRESSURE TO A SENSITIZED AREA OF SAID MATERIAL COMPRISING: A DEVELOPMENTPLATEN HAVING A FIRST CAVITY IN ONE SIDE THEREOF, A SEAL MEMBERSURROUNDING SAID FIRST CAVITY AND SHAPED TO ENCLOSE SAID SENSITIZEDAREA, A BACK-UP PLATEN OPERATIVE TO HOLD SAID SENSITIZED AREA AGAINSTSAID SEAL WHEREBY A DEVELOPMENT CHAMBER IS FORMED WITH SAID FIRSTCAVITY, A SECOND CAVITY ON THE OPPOSITE SIDE OF SAID DEVELOPMENT PLATEN,SEALING MEANS FOR SAID SECOND CAVITY WHEREBY AN AIR ENTRAPMENT CHAMBERIS FORMED, A PORT FOR CONDUCTING SAID PRESSURIZED SUBSTANCE INTO SAIDFIRST CAVITY SUBSTANTIALLY AT THE CENTER THEREOF WHEREBY SAID SUBSTANCEWILL SPREAD OUT IN ALL DIRECTIONS THROUGHOUT SAID DEVELOPMENT CHAMBER,AND A PLURALITY OF INDIVIDUAL PORTS ARRANGED AROUND THE PERIPHERY OFSAID FIRST CAVITY WHICH COMMUNICATE WITH SAID AIR ENTRAPMENT CHAMBERWHEREBY ENTRAPPED AIR IN SAID DEVELOPMENT CHAMBER IS FORCED BY SAIDSUBSTANCE TO FLOW INTO SAID AIR ENTRAPMENT CHAMBER THUS ENABLING SAIDSENSITIZED AREA TO BE CONTACTED BY SAID FLUID SUBSTANCE IN THE ABSENCEOF AIR.